Yarn handling



p 1960 w. o. YOUNG, JR

YARN HANDLING Filed Sept. 16, 1954 INVENTCR WILLMM Oll ER YOUNQ,JR.

ATTORNEY United States, Patent YARN HANDLING William Oliver Young, Jr.,Camden, S.C., assignor to E. I. du Pont de Nemours and Company,Wilmington, Del., a corporation of Delaware Filed Sept. 16, 1954, Ser.No. 456,388

9 Claims. (Cl. 2267) This invention relates to apparatus for preventingfilament wraps on guiding or delivery rolls used in the processing oftextile yarn or tow and to an improved method of guiding and advancing arunning yarn or tow of filaments. The invention'is especially directedto delivery rolls capable of advancing yarn and tow under substantialtension and releasing them to fall freely on to a suitable collectingsurface without wrap formation.

Whenever a yarn or tow consisting of many fine filaments is processedand conducted by means of rolls, the tendency of the filaments to adhereto the rolls, strip back, and ultimately wrap therearound is everypresent. The condition becomes an even greater problem when the towleaves the rolls in a state of very low tension as in the .case of freefalling or piddling on to a collecting belt or other surface. Variousproposals for reducing wraps such as air wipers, doctor blades and thelike have met with some success in improving continuity of operation,but these have not been altogether satisfactory solutions to the problemsince the tendency to wrap is still present and the corrective measuremerely attempts to prevent a strip back from growing to seriousproportions.

It is, therefore, an object of this invention to provide a novel yarn,strand or tow guiding or advancing appartus. Another object of thisinvention is to provide an improved method of handling running yarns andtows of filaments without encountering filament wraps. Other objectswill be apparent from the description of the invention that follows.

In the figures:

Figure 1 is a side section view taken on line 1-1 of Figure 2, showingone of the rolls in section, and

Figure 2 is a front section taken on line 22 of Figure 1, including, forconvenience, a showing of a pair of rolls in nip formation by dottedlines since they are to the left of line 2--2.

The objects of this invention are accomplished by the use of guiding ordelivery rolls for running yarns, strands, tows and the like providedover their entire filamentcontacting surfaces with closely spaced,minute passages for air or other gaseous fluid, such as nitrogen, carbondioxide or dry steam, to be forced outwardly from Within and thusprevent any tendency for the filaments to wrap therearound. The veryminute size and very close spacing of the gaseous fluid passages coupledwith an internal pressure of from about 50 to about 100 pounds persquare inch (gauge) causes an untensioned filament to float on the fluidlayer surrounding the roll without any adherence to the roll surface.essentially a surface phenomenon and my little disturbance can beobserved at over /4 inch or so away from the roll. Of course, when therolls are being used to form a nip and filamentary material is passedtherebetween, one roll being pressed against the other, floating.

will not occur, but should a filament become broken or untensionedbeyond the nip, the floating effect will prevent it from wrapping.

The effective gas flow is.

The process thus comprises feeding filamentary ma terial to a rotatingmember which has a foraminous shell and a porous working surface,through which shell a fluid under pressure passes from the interiorthrough the pores to the outside surface and into the atmosphere. Arotating surface emits the high velocity fluid which exerts a localizedradial repulsing force against the filamentary material at all times.This force is effective, depending upon the pressures used and pressuredrops occurring, usually within A inch or so away from the roll, andacts on the filamentary material at all times that the material iswithin such distances from the working surface. This effectivelyprevents wraps.

With reference to the drawings, 1 is a frame suitably mounted on asupport (not shown). Within this frame are located shafts for drivingand supporting two (see Figure 2) external tow delivery rolls 2, of thetype previously mentioned, forming a nip 41 through which tow 42 passes.One of these shafts 3 is fixedly supported in suitable bearings mountedon the inside surfaces of the front and back walls of the frame whileshaft 4 is mounted on a subframe 5 for movement toward and away from thefixed roll shaft 3. The subframe comprises a plate 6 carrying two pillowbearing blocks 7 supporting shaft 4. To the upper end of plate 6 arefastened two mounts 8 for suspending plate 6 from pivot shaft 9 which isfastened to the mounts by means of set screws in tapped holes 10. Thetwo blocks 7 and mounts 8 may be seen in Figure 1. Shaft 9 is supportedin two bearings 11 fastened to the inside front and back walls of theframe II. To the bottom of plate 6 is welded a plate support .12carrying a bracket 13 to which is attached the end of the piston rodfrom an air cylinder 14 which exerts a constant pressure tending to keeproll 2 on shaft 4 against roll 2 on shaft 3. Air cylinder 14 ishingeably mounted to bracket 15 fastened to the side wall of frame 1. I

The delivery roll shafts 3 and 4 are driven at the same speed by meansof sprockets and a chain 17 as shown in the figures. Shaft 16 with asprocket is the driver, it being driven preferably from a motor througha PIV or other variable drive to give the desired speed control. Inaddition to passing around the sprockets on shafts 3 and 4, the chain 17passes around an idler sprocket on shaft 19 so mounted as to maintainsubstantially constant tension on the chain regardless of the positionof the movable shaft 4. Shaft 19 is rotatably supported in two endpillow block bearings 20 fixed to plate 21 which is swingable about thecenter of shaft 22 which, in turn, is supported by a bracket 23 with twobearings 24 to the wall of frame 1. At the opposite end of plate 21 is abracket 25 and to this is pinned a clevis fastened to the end of thepiston shaft of air cylinder 26 which is attached to the bottom of frame1 by means of bracket 27.

As shown in Figure l by the cross-sectional view of the roll 2 mountedon shaft 4, the delivery rolls 2 are constructed of a foraminouscylindrical shell 30, for instance, of sintered metal such asmicroporous stainless steel or microporous bronze which provide aninfinite number of very fine passages for air or the like.cross-sectional area of each passage preferably is of the same order ofmagnitude as the cross-sectional area of an individual filament, forinstance, about to about 500 square microns (about 10 to about 25microns diameter if the openings were circular). The foraminouscylindrical shells are concentrically supported near the end of theshafts 3 and 4 by two end flanges 31 and 32, which flanges are keyed tothe shafts to insure rotation therewith. Thrust collars 33 serve tospace the rolls from the frame and together with cap screws 34 and twogaskets 35 for each roll provide sufficient end pressure to insure anair tight fit between the ends of the foraminous shell and the PatentedSept; 20, 1960 The flanges. The shafts 3 and 4 are axially drilled fromend to end, and connecting with the resultant passageway 37 are aplurality of radial holes 36 between the end flanges 31 and 32. At theroll end of the shaft, the axial drilling is blanked off by cap screw34, providing for the introduction of a gaseous fluid such as air intothe spaces between the shells 30 and the shafts. For protection of theforaminous cylindrical shells when no yarn or tow is therebtween, theouter diameter of the end flanges is made very slightly larger indiameter, e.g. 0.008 inch, thus preventing the shell surfaces forcontacting each other.

At the end of shafts 3 and 4 opposite to the location of the rolls,there is provided a gas-tight chamber. The cap plate 38 of this chamberis tapped for a pipe connection 39 communicating with a source of air orother gaseous medium at the desired pressure. The connection to thefixed roll shaft 3 may be rigid, but to the movable roll shaft 4 aflexible connection is required. When air is supplied at 70 or 80 poundsper square inch gauge pressure, this pressure is substantiallymaintained at the chamber within the tow delivery rolls and a pressuredrop of substantially this amount takes place in traversing themicroporous shell.

While yarns and filament bundles of any size may be effectively guidedor advanced by the apparatus of this invention, this specificarrangement just described is especially suited to the handling of verylarge tows or filament bundles having a total denier of 100,000 and morecomprised of 20,000 or more filaments. By properly setting the rollpressure and surface speed of the rolls, very effective uniformadvancement of the filament bundle is accomplished without slip. In viewof the very fine miscroscopic openings in the rolls, it is desirable tofilter the air or other gaseous medium used carefully to avoid stoppageof the fine openings. Gas pressures of at least 50 pounds per squareinch gauge are necessary and pressures as high as 100 pounds per squareinch are satisfactory. Air pressures of about 70 to about 80 pounds persquare inch gauge are preferred.

Even though a tow of filaments is fed vertically down into the bite ofthe rolls at a tension of 50 or more pounds and drops vertically downfrom between the rolls at a very low tension (due only to the weight ofthe tow between the nip and the point of collection), there is not theslightest tendency for filaments to wrap around either of the rolls. Auniform outwardly moving layer of gas envelops the foraminouscylindrical part of the roll for a distance of about inch except at thebite and, even here, air may be emitted when the surface is suflicientlyclear of filaments to permit the passage of the gas. The actualconsumption of air or other gas is surprisingly small and yet anuntensioned filament bundle wet or dry cannot be made to adhere to theroll surface.

While the need for wrap-preventing guide rolls of the type hereindescribed is not as great as for delivery or feed rolls, such guiderolls may be used at times advantageously. Single guide rolls aregenerally used at any one position since the object is largely a matterof changing direction of the running yarn or the like and in such use,the roll may be yarn driven or mechanically driven as desired. Thus,while the figures relate to the use of the rolls of this invention inpairs, a single roll can be used with advantage as a directional guideroll or in reducing frictional contact in the advancing of filaments.Obviously, the use of this type roll for guiding permits many changesand simplification of the design.

The process and apparatus of this invention may be applied to any of thesynthetic or natural filament or fiber bundles. For example, regeneratedcellulose tows, cellulose acetate and other cellulose derivative tows,polyamide filament bundles, polyester filament bundles,polyacrylonitrile filament bundles, as well as slivers, tops and thelike of cotton, wool, linen and similar materials may be handled inaccordance with this invention.

Any departure from the above description which conforms to the presentinvention is intended to be included within the scope of the claims.

I claim:

1. The process of feeding filamentary material over and beyond arotatable member which comprises feeding said material to said rotatingmember, simultaneously passing a gaseous fluid under uniform pressureinto the interior of said member, and forcing said fluid through amultiplicity of randomly spaced minute passages which are distributedover the entire peripheral surface of said member to form a continuousgaseous layer about said member, said gaseous layer exerting acontinuous uniform radial repulsing force against the filamentarymaterial thereby preventing the material from wrapping around saidmember.

2. The process of claim 1 wherein said pressure is about 50 to poundsper square inch gage and the cross-sectional area of said passages isfrom about 100 to 500 square microns.

3. The process of claim 1 wherein said filamentary material is in theform of a tow.

4. The process of transferring and delivering tow comprised of finefilamentary strands which comprises passing said filamentary strandsthrough a nip formed by two rotatable members positioned in side-by-siderelationship, forming a continuous gaseous layer about each of saidmembers by passing a gaseous fluid under uniform pressure into theinterior of each of said rotatable members and forcing said fiuidthrough a multiplicity of randomly spaced minute passages which aredistributed over the entire peripheral surface of said members, saidgaseous layer exerting a continuous uniform radial repulsing forceagainst said filamentary strands thereby preventing said strands fromwrapping about said members.

5. Apparatus adapted to transfer and deliver tow comprised of finefilamentary strands which comprises a roll rotatably mounted on a shaft,said roll having a hollow chamber therein and a smooth peripheralsurface containing a multiplicity of randomly spaced minute passages incommunication with said hollow chamber, said passages being distributedover the entire peripheral surface of said roll, means for delivering agaseous fluid under pressure to said hollow chamber whereby said fluidpasses outward? 1y through said passages forming a continuous gaseouslayer about said surface, and means for passing said tow over thesurface of said roll.

6. The apparatus of claim 5 in which the average di ameter of thepassages is from about 10 microns to 25 microns.

7. Apparatus adapted to transfer and deliver tow comprised of finefilamentary strands which comprises two rolls rotatably mounted inside-by-side relationship to form a nip, means for spacing said rollsapart to permit the passage of said filamentary strands therebetween,each of said rolls having a hollow chamber therein and a smoothperipheral surface, said peripheral surface containing a multiplicity ofrandomly spaced minute passages in communication with said hollowchamber, said passages being distributed over the entire peripheralsurface of each of said rolls, means for supplying a gaseous fluid underpressure to said hollow chamber whereby said fluid passes outwardlythrough said passages forming a continuous gaseous layer about saidsurfaces, and means for passing said tow through the nip formed by saidrolls.

8. The apparatus of claim 7 in which the passages have an averagediameter between 10 microns and 25 microns.

9. The apparatus of claim 7 in which one of the rolls is pivotallymounted.

(References on following page) References Cited in the file of thispatent UNITED STATES PATENTS 1 6 Nazel Feb. 16, 1915 Ruby Apr. 24, 1917Meyer May 31, 1927 Knebusch et al Sept. 26, 1939 McDermott Aug. 17, 1948Slayter Jan. 3, 1956

